A recent study published in The has brought to light a disturbing outbreak in Tamil Nadu's Tirupattur district, where eight individuals died in 2023 after contracting neuromelioidosis, a rare and severe brain infection, traced back to a dental clinic in Vaniyambadi town.
The source of the outbreak was identified as a contaminated saline bottle used during dental procedures.
The incident, which went unreported by government bodies, was uncovered through a detailed investigation led by a multidisciplinary team including doctors from CMC Vellore, ICMR-NIE, and the Tamil Nadu Directorate of Public Health. The team discovered that poor sterilization practices at the dental facility were the root cause.
According to the study, the infection spread after a periosteal elevator, a surgical instrument, was used to puncture the seal of a saline bottle. The bottle was then loosely closed and reused on multiple patients, resulting in at least ten infections, of which eight proved fatal. Dr. Angel Miraclin Thirugnanakumar, the study's lead author from CMC's Department of Neurological Sciences, stated that the 80% fatality rate was due to the bacteria entering directly through the nerves during oral procedures, bypassing the bloodstream.
Neuromelioidosis is caused by Burkholderia pseudomallei, a bacterium commonly found in soil and water in tropical climates. It severely affects the central nervous system, particularly the brain and spinal cord. Symptoms typically include fever, headache, blurred vision, slurred speech, and, in some cases, facial paralysis. Genome sequencing revealed that the strain involved in this outbreak possessed a gene that makes it particularly aggressive in attacking the brain.
Between July 2022 and April 2023, researchers identified 21 cases of neuromelioidosis. Among them, ten patients had been treated at the dental clinic; of these, eight died. The other 11 patients, who had no link to the clinic, experienced only one fatality, marking a much lower death rate of 9%. Geographically, 17 of the cases occurred in Tirupattur, two in Ranipet, and one each in Tiruvannamalai and Krishnagiri.
Data showed that patients infected through the dental clinic succumbed to the illness much more quickly. On average, death occurred 16 days after symptoms appeared and nine days after hospitalisation, compared to 56 days and 38 days respectively for those not exposed via the clinic.
Dr. T. S. Selvavinayagam, Tamil Nadu's Director of Public Health, acknowledged that the findings would assist in identifying similar cases for better outbreak response and local containment. "We've taken corrective steps to control the spread. This serves as a crucial reminder for healthcare providers to strictly follow infection control protocols," he said.
The first alert came on 9 May 2023, when CMC Vellore reported a spike in neuromelioidosis cases, some linked to the dental clinic. A few days later, a coordination meeting was held with healthcare providers in Tirupattur and nearby districts. A medical team was promptly formed to investigate and trace the source.
However, by the time officials arrived at the dental facility, it had already been disinfected, closed, and its water supply cut off-reportedly in response to public outrage. Still, scientists managed to isolate Burkholderia pseudomallei from a previously opened saline bottle. No contamination was found in sealed, unused bottles. Genetic sequencing confirmed the findings.
Interestingly, the clinical presentations varied between those linked to the clinic and those who were not. Non-clinic cases often showed salivary gland swelling, cheek inflammation, and enlarged lymph nodes. In contrast, patients who had visited the dental clinic exhibited more severe and faster-developing symptoms such as facial cellulitis and soft tissue abscesses, likely due to ingestion of the tainted saline.
This tragic event underscores the critical importance of strict hygiene protocols in medical and dental facilities and raises urgent questions about regulation and oversight in private clinics.
